Polarized neutron beta decay studies in Tennessee

PNAB aims to measure the A and B correlation parameters in free neutron beta decay, which require a polarized neutron beam. The collaboration will use the existing Nab spectrometer at the Fundamental Physics Beamline of the Spallation Neutron Source at Oak Ridge National Lab to perform this high precision measurement. In combination with others, this measurement will shed light on recent hints for a violation of the unitarity of the Cabbibo-Kobayashi-Maskawa matrix. I will discuss motivation and design, with a particular focus on the methods to provide very high polarization of cold neutrons, allowing for a precision measurement of it.